This invention relates to novel oxetanocins exhibiting physiological activities such as immunosuppressive activity, antiviral activity, and the like.
As immunosuppressive agents, alkylating agents, antimetabolites, antibiotics, steroidal agents, folic acid antagonists, and vegetable alkaloids have hitherto been known. On the other hand, oxetanocin (OXT-A) itself is disclosed in Journal of Antibiotics, Vol. 39, No. 11, pp. 1623-25 (1986) and Japanese Patent Application Kokai (Laid-Open) No. 61-293,992 (EP No. 0 182 315).
Among the prior immunosuppressive agents, steroidal agents are said to exhibit their immunosuppressive action owing to their anti-inflammatory action and lympholytic action. Because of their diverse action, their use is accompanied by various side reactions, as is well known. It is also known that the other immunosuppressive agents belong to the so-called cytotoxic substances. Thus, it is desired to develop an agent selectively exercising its activity only on immunocomponent cells and exhibiting side reactions as mild as possible.